1004 THE AMERICAN NATURALIST. [Vor. XXXV. 
the alimentary canal, it very rapidly becomes a granular mass 
recognizable as an egg only through its known origin. 
That these disintegrating eggs actually serve the animal as 
food is evident from the fact that in a number of cases the 
passage of the eggs to the alimentary canal and their diges- 
tion was followed in a few days by the appearance and partial 
growth of new oócytes in the gonads, each individual worm 
being isolated meanwhile in clear water and without other 
food during the whole period. In cases where the eggs were 
normally laid by similarly isolated specimens, new oocytes 
appeared only when the first set had been laid almost imme- 
diately after the beginning of the experiment, so that the 
animal was comparatively fresh and probably still contained a 
certain surplus of nutritive material. Moreover, these oócytes 
never reached a large size and usually underwent disintegra- 
tion at a later period. 
The manner in which the disintegrating egg cells reach the 
alimentary canal is somewhat obscure. Rupture of the walls 
of the gonad and the intestine is necessary. I believe that 
this rupture is brought about chiefly in consequence of the 
increasing disproportion between the size of the body and the 
size of the egg as the starving animal decreases in size, and 
that finally the egg becomes too large for the lateral regions 
of the body and is forced into the alimentary canal by the 
movements and contractions of the body. A study of sec- 
tions reveals a decreasing thickness in the walls of the intes- 
tine and gonads, as well as other histological changes, but 
these need not be discussed here. 
The passage of the egg cells to the intestine occurs in pieces 
which have been deprived of head and brain, as well as in 
normal individuals. 
ABSENCE OF FISSION. 
Benham (97) has described a process of spontaneous fission 
in Carinella which probably serves as a means of distribution 
of the sexual products, and Wilson (00) states that Cere- 
bratulus fragments spontaneously at the close of the breeding 
